Numerous businesses need to ship large quantities of goods and utilize cartons, particularly corrugated cartons, to hold the goods during shipment. Consequently, such businesses desire to be able to rapidly erect, fill, close, and seal their shipping cartons. FIG. 1 illustrates a typical prior art carton 10 having side surfaces 12 and end surfaces 14. Carton 10 also includes a bottom surface (not shown). Closure panels 16 extend upwardly from side surfaces 12, while closure panels 18 extend upwardly from end surfaces 14. FIG. 2 depicts a carton blank 20 from which a carton 10 might be erected. Carton blank 20 includes the panels 12-18 shown in FIG. 1 and also bottom panels 22 and 24 which correspond, respectively, with the top panels 16 and 18. Preferably, carton blank 20 also includes a sealing strip 26 which extends from one panel, such as the outermost end panel 14 as illustrated in FIG. 2, so that when the carton is erected, strip 26 can be sealed to the adjacent side panel 12, as illustrated in FIG. 1. To enable the necessary folds, panels 16 and 18 must be separated by slots 19, and likewise panels 22 and 24 must be separated by slots 25. Consequently, it is time consuming and expensive to form blank 20.
Erecting carton 10 from blank 20 requires folding panels 22 and 24 inwardly 90°, making 90° folds at the junctions of the panels 12 and 14, sealing the junction of the two bottom panels 22, and sealing the sealing strip 26 to the adjacent panel. The several folds must be performed in sequence, and so require significant time.
Once carton 10 is filled with goods, panels 18 are folded inwardly to overlie those goods, and then panels 16 are folded over panels 18 and the goods to close the carton. The carton then might be sealed, for example by applying a tape along the junction of the two panels 16. FIG. 3 depicts the resulting closed carton 10. The four separate closure panels 16, 18 must be separately folded, with panels 18 folded before panels 16. Consequently, a significant time is required to close carton 10. The junction of the two top panels 16 must then be sealed.
While these various operations might be mechanized, still the large number of steps results in the operations being time consuming. In addition, different sizes of cartons require different equipment sizes in order to perform the operations mechanically. This requires either different apparatuses for different carton sizes, or an apparatus which is adjustable in size, then necessitating the adjustment of the size each time the carton size changes. In addition to being time consuming, these approaches are expensive.
FIG. 9 depicts a carton 162 having side panels 32, 52 and end panels 42, 62 which bridge the side panels. First and second top panels 72, 112 extend upwardly from side panels 32, 52, while first and second fold-in panels 92, 132 extend upwardly from end panels 42, 62 and bridge the top panels. Panels 72, 92, 112 and 132 are joined to their respective side panels and end panels 32, 42, 52, 62 by 90° fold lines 74, 94, 114, and 134. Each fold-in panel 92, 132 has a pair of fold lines 152 which extend from a point substantially at the center of the panel upper edge opposite fold line 94, 134 to the corners of the panel 92, 132 at the ends of fold line 94, 134. Pressure on any panel 72, 92, 112 or 132 can cause the fold-in panels 92, 132 to be folded inwardly on the fold lines 94, 134, forming a 180° fold at each fold line 152 and causing top panels 72, 112 to fold over the top of carton 162, as depicted in FIGS. 10 and 11. Continued such pressure will bring carton 162 to its closed condition, depicted in FIG. 12.
The necessity to make a 180° fold in each fold line 152 has limited the applicability of this type of carton. By way of example, U.S. Pat. No. 2,439,435 shows such a carton used for moisture-proof packaging. However, to permit the 180° folds that are necessary, the carton of this patent is made of paper board. U.S. Pat. No. 5,143,281 shows such a carton made of cardboard having a foil to provide a liquid-tight package. U.S. Pat. No. 5,078,315 likewise shows a liquid containing package having 180° folds. This package is formed of a laminate of paper, thermal plastic, and possibly aluminum foil. U.S. Pat. No. 2,810,506 shows a carton with 180° folds which is made of a sheet material. U.S. Pat. No. 5,056,707 similarly shows a carton made of a sheet material coated with thermoplastics to permit containing of liquids. All of thin material can readily be folded 180°. However, cartons made of such thin materials are unsuitable for heavy duty cartons used for shipping.
U.S. Pat. No. 915,579 shows a shipping container made of a corrugated material and utilizing 180° folds on end flaps. However, the end flaps are first crushed to permit such folding. This, of course, destroys the corrugations and weakens the materials. U.S. Pat. No. 2,926,777 also shows a shipping container made of a corrugated material and having 180° folds. However, to permit such folds in the corrugated material, the fold lines are scored. This severs the corrugation and weakens the material.